Apparatus and method of delivering a fluid using direct proppant injection

ABSTRACT

An apparatus and method for delivering a fluid mixture using direct injection to a mixing apparatus. The apparatus including a proppant storage vessel configured to contain therein a proppant material and output a proppant output flow at ambient pressure to a solid feed pump assembly. The apparatus further including a fracturing fluid storage vessel configured to contain therein a fracturing fluid and output a fracturing fluid output flow at a fracture fluid blending pressure. The solid feed pump assembly configured to output to a mixing apparatus, a proppant output flow at the fracture fluid blending pressure. The mixing apparatus configured to output a fluid mixture of the proppant and the fracturing fluid at the fracture fluid blending pressure. The mixing apparatus coupled to a high pressure pump assembly and configured to deliver the fluid mixture therein to a downstream component at an injection pressure.

BACKGROUND

Embodiments disclosed herein relate generally to an apparatus and methodof delivering a fluid mixture into a wellbore.

Hydraulic fracturing, commonly known as hydrofracking, or simplyfracking, is a technique used to release petroleum, natural gas or othersubstances for extraction from underground reservoir rock formations. Awellbore is drilled into the reservoir rock formation, and a treatmentfluid is pumped which causes fractures and allows for the release oftrapped substances produced from these subterranean natural reservoirs.Current wellhead fracking systems utilize a process wherein a slurry offracturing fluid and proppant (e.g. sand) is created and then pumpedinto the well at high pressure. When water-based fracturing fluids areused, the proppant, water and appropriate chemicals can be mixed atatmospheric pressure and then pumped up to a higher pressure forinjection into the well. However, if fluids other than water (e.g.liquid CO₂ or liquid propane) are used as the fracturing fluid, thenthese fluids must be kept at a sufficient pressure throughout thehydraulic fracturing system to avoid undesired vaporization. As aresult, the blending of these fluids with proppant, chemicals, etc. mustalso be accomplished while the fluids are kept under a sufficiently highpressure. Current pressurized blenders exist for this purpose.

Known pressurized blenders capable of blending these vaporizingfracturing fluids with the proppant at a suitably high pressure utilizea pressurized proppant storage vessel arrangement to feed and meter theproppant into the pressurized fracturing fluid. These known lock-hopperbased pressurized blenders require pre-loading with the proppant to beutilized during a given fracture stage. The pressurized proppant storagevessels used typically have a capacity in the range of 20-40 tons ofproppant (e.g., sand). The limited volume capacity of the proppantstorage vessel system provides for limited amounts of proppant to beblended with the fracturing fluid. If the fracturing design requiresmore sand, then multiple blenders must be used. In addition, these knownpressurized blenders require an undesirably long elapsed time to reloadthem with proppant for the next fracture stage. In some instances, somepressurized blender operations require the blender unit be movedoff-site to another location for the purpose of reloading with proppant,also requiring an undesirably long time and potentially adding to thetruck traffic associated with fracturing operations. In many instances,the limited capacity requires specialized logistics and on-pad (oroff-pad) proppant handling equipment to be used in conjunction with theproppant storage vessel based pressurized blenders.

Accordingly, there is a need for an improved pumping system and methodfor delivering treatment fluid into a wellbore that will enable theblending and pumping of essentially unlimited quantities of proppant andfracturing fluid to form the fluid mixture. The ability to deliverunlimited quantities will provide for continuous operation of thepressurized blender and sand feeding equipment, enable fracture plans tobe based upon reservoir stimulation requirements without imposingequipment constraints, and therefore providing overall a more efficientsystem.

BRIEF SUMMARY

These and other shortcomings of the prior art are addressed by thepresent disclosure, which provides an apparatus and method of deliveringa fluid using direct proppant injection to a pressurized blender.

In accordance with an embodiment, provided is an apparatus fordelivering a fluid mixture comprising: a proppant storage vessel, asolid feed pump assembly, a fracturing fluid storage vessel, a mixingapparatus and a high pressure pump assembly. The proppant storage vesselis configured to contain therein a proppant material and output aproppant output flow at ambient pressure. The solid feed pump assemblyis coupled to the proppant storage vessel. The solid feed pump assemblyincluding a proppant inlet in fluidic communication with the proppantstorage vessel proppant output flow. The solid feed pump assembly isconfigured to output a proppant output flow at or above a fracture fluidblending pressure, wherein the fracture fluid blending pressure isgreater than the ambient pressure. The fracturing fluid storage vesselis configured to contain therein a fracturing fluid and output afracturing fluid output flow at the fracture fluid blending pressure.The mixing apparatus is coupled to the solid feed pump assembly. Themixing apparatus including a proppant inlet in fluidic communicationwith the solid feed pump assembly proppant output flow and a fracturingfluid inlet in fluidic communication with the fracturing fluid outputflow. The mixing apparatus is configured to mix the proppant output flowand the fracturing fluid output flow therein and output a fluid mixtureof proppant and fracturing fluid at the fracture fluid blendingpressure. The high pressure pump assembly is coupled to the mixingchamber and configured to deliver the fluid mixture therein to adownstream component at an injection pressure, wherein the injectionpressure is greater than the fracture fluid blending pressure.

In accordance with another embodiment, provided is an apparatus fordelivering a fluid mixture comprising: a proppant storage vessel, asolid feed pump assembly, wherein the solid feed pump assembly is one ofa Posimetric® pump assembly, an eductor pump assembly or a rotarypositive displacement pump assembly, a fracturing fluid storage vessel,a mixing apparatus and a high pressure pump assembly. The proppantstorage vessel is configured to contain therein a proppant material andoutput a proppant output flow at ambient pressure. The solid feed pumpassembly is coupled to the proppant storage vessel and including aproppant inlet in fluidic communication with the proppant storage vesselproppant output flow. The solid feed pump assembly is configured tooutput a proppant output flow at a fracture fluid blending pressure,wherein the fracture fluid blending pressure is greater than the ambientpressure. The fracturing fluid storage vessel is configured to containtherein a fracturing fluid and output a fracturing fluid output flow atthe fracture fluid blending pressure. The mixing apparatus is coupled tothe solid feed pump assembly and including a proppant inlet in fluidiccommunication with the solid feed pump assembly proppant output flow anda fracturing fluid inlet in fluidic communication with the fracturingfluid output flow. The mixing apparatus is configured to mix theproppant output flow and the fracturing fluid output flow therein andoutput a fluid mixture of proppant and fracturing fluid at the fracturefluid blending pressure. The high pressure pump assembly is coupled tothe mixing chamber and configured to deliver the fluid mixture thereinto a downstream component at an injection pressure, wherein theinjection pressure is greater than the fracture fluid blending pressure.

In accordance with yet another embodiment, provided is a method fordelivering a fluid mixture, comprising: providing an input of a proppantmaterial at ambient pressure to a proppant storage vessel, the proppantstorage vessel configured to output a proppant output flow at ambientpressure; providing an input of a fracture fluid at a fracture fluidblending pressure to a fracture fluid storage vessel, the fracture fluidstorage vessel configured to output a fracture fluid output flow at thefracture fluid blending pressure; inputting the proppant output flow atambient pressure from the proppant storage vessel into a solid feed pumpassembly wherein the pressure of the proppant output flow is increasedto a fracture blending pressure; inputting the proppant output flow atthe fracture fluid blending pressure and a fracture fluid output flow ata fracture fluid blending pressure into a mixing apparatus; mixing theproppant output flow and the fracturing fluid output flow therein themixing apparatus and outputting a fluid mixture of proppant andfracturing fluid at the fracture fluid blending pressure; increasing thepressure of the output fluid mixture in a high pressure pump; anddelivering the high pressure fluid mixture to one or more downstreamcomponents.

Other objects and advantages of the present disclosure will becomeapparent upon reading the following detailed description and theappended claims with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE FIGURES

The above and other features, aspects, and advantages of the presentdisclosure will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein

FIG. 1 is a schematic diagram of an apparatus for delivering a fluidmixture using a solid feed pump assembly for direct proppant injectionto a pressurized mixing apparatus constructed in accordance with anembodiment;

FIG. 2 is a schematic diagram of an apparatus for delivering a fluidmixture using a Posimetric® pump assembly for direct proppant injectionto a pressurized mixing apparatus constructed in accordance with anotherembodiment;

FIG. 3 is a schematic diagram of an apparatus for delivering a fluidmixture using a eductor pump assembly direct proppant injection to apressurized mixing apparatus constructed in accordance with stillanother embodiment;

FIG. 4 is a schematic diagram of an apparatus for delivering a fluidmixture using a pressurized rotary positive displacement pump assemblyfor direct proppant injection to a pressurized mixing apparatusconstructed in accordance with still another embodiment; and

FIG. 5 is a schematic block diagram of a method of delivering a fluidmixture using a direct proppant injection to a pressurized mixingapparatus constructed in accordance with still another embodiment.

DETAILED DESCRIPTION

This disclosure will be described for the purposes of illustration onlyin connection with certain embodiments; however, it is to be understoodthat other objects and advantages of the present disclosure will be madeapparent by the following description of the drawings according to thedisclosure. While preferred embodiments are disclosed, they are notintended to be limiting. Rather, the general principles set forth hereinare considered to be merely illustrative of the scope of the presentdisclosure and it is to be further understood that numerous changes maybe made without straying from the scope of the present disclosure.

Preferred embodiments of the present disclosure are illustrated in thefigures with like numerals being used to refer to like and correspondingparts of the various drawings. It is also understood that terms such as“top”, “bottom”, “outward”, “inward”, and the like are words ofconvenience and are not to be construed as limiting terms. It is to benoted that the terms “first,” “second,” and the like, as used herein donot denote any order, quantity, or importance, but rather are used todistinguish one element from another. The terms “a” and “an” do notdenote a limitation of quantity, but rather denote the presence of atleast one of the referenced item. The modifier “about” used inconnection with a quantity is inclusive of the stated value and has themeaning dictated by the context (e.g., includes the degree of errorassociated with measurement of the particular quantity).

As used herein, the process of forming of a fluid mixture includesmixing a fluid with a powdered or particulate material, such asproppant, a powdered dissolvable or a hydratable additive (prior tohydration). In a continuous treatment or in a continuous part of a welltreatment, the fluids are handled as fluid streams.

Referring to the drawings wherein, as previously stated, identicalreference numerals denote the same elements throughout the variousviews, FIG. 1 depicts in a simplified block diagram, elements of anapparatus for delivering a fluid mixture 100 including direct proppantinjection to a pressurized blender, or mixing apparatus, according to anembodiment. The apparatus 100 includes a proppant storage vessel 102coupled to a solid feed pump assembly 104. The proppant storage vessel102 is coupled to the solid feed pump assembly 104, at an inlet port 106of the solid feed pump assembly 104. More specifically, an outlet 108 ofthe proppant storage vessel 102 is configured in fluidic communicationwith the inlet 106 of the solid feed pump assembly 104. The proppantstorage vessel 102 is configured as a traditional unpressurized storagetype vessel and includes a body 110 configured to hold a proppantmaterial 112 therein at atmospheric pressure. The proppant storagevessel 102 may further include a proppant material inlet 114 coupled toa proppant material loading device 116 and a source of proppant material(not shown). In an embodiment, the proppant material 112 may becomprised of a sand, or other material commonly utilized as proppant inpumping operations. The proppant storage vessel 102 provides adequatestorage and loading capabilities to allow for a continuous supply ofproppant material 112 to solid feed pump assembly 104.

During operation, the proppant storage vessel 102 may be loaded by thematerial loading device 116, such as a screw auger, conveyor, or anyother low pressure means configured to move the proppant material 112from a proppant supply source (not shown) to the proppant storage vessel102. Alternate means for providing the proppant material 112 to theproppant storage vessel 102 are anticipated herein.

The solid feed pump assembly 104 includes a pump assembly capable ofreceiving a proppant output flow 118 at atmospheric pressure via outlet108 and inlet 106 and then providing at solid feed pump assembly outlet120, a proppant output flow 122 at a fracture fluid blending pressure,wherein the fracture fluid blending pressure is greater than the ambientpressure. In an embodiment, the fracture fluid blending pressure is in arange of about 50 psi to 400 psi, and preferably at a pressure ofapproximately 300 psi.

A pressurized blender, or mixing apparatus, 124 is configured to receivethe proppant output flow 122 via a proppant inlet 126. A fracturingfluid storage vessel 128 is provided in fluidic communication via anoutlet 130 with the pressurized mixing apparatus 124 via a fracturingfluid inlet 132. The fracturing fluid storage vessel 128 is configuredfor storage of a fracturing fluid 134 at a required temperature andstorage pressure, and more particularly at or above the fractureblending pressure. The pressurized mixing apparatus 124 is configured toreceive a fracturing fluid output flow 136 at the fracture fluidblending pressure via the inlet 132. In an embodiment, the fracturingfluid storage vessel 128 is configured to permit a minimal amount of thefracturing fluid output flow 136 to enter the solid feed pump assembly104 so as to provide for moistening of the proppant material toaccomplish pumping therethrough of the proppant material 112. It shouldbe understood that while anticipated is the permitting of a minimalamount of fracturing fluid output flow 136 to enter the solid feed pumpassembly 104, in contrast to previous known pumping systems, the amountof fracturing fluid output flow 136 that is allowed to enter the solidfeed pump assembly 104 is not sufficient to provide for the formation ofa dense proppant/fluid slurry to be pumped through the pump assembly104.

During operation, the proppant output flow 122 and the fracturing fluidoutput flow 136 are blended, or mixed, within the pressurized mixingapparatus 124 and delivered as a fluid mixture output flow 138 via anoutlet 140 of the pressurized mixing apparatus 124 to a high pressurepump assembly 142. In alternate embodiments, a fracture fluid boosterpump 141 may be provided inline between the mixing apparatus 124 and thehigh pressure pump assembly 142, or alternatively provided as part ofthe functionality of the high pressure pump assembly 142. The fluidmixture output flow 138 is output at the fracture blending pressure. Thefluid mixture output flow 138 is received via a fluid mixture inlet 144of the high pressure pump assembly 142. The high pressure pump assembly142 is configured to deliver the fluid mixture output flow 138 receivedtherein to a downstream component 146 at an injection pressure, whereinthe injection pressure is greater than the fracture fluid blendingpressure. More specifically, in an embodiment, the high pressure pumpassembly 142 is configured to deliver a high pressure fluid mixtureoutput flow 148 via an outlet 150 of the high pressure pump assembly 142to an inlet 152 of the downstream component 146, such as a well head154.

The inclusion of the solid feed pump assembly 104 in apparatus 100 willallow unlimited amounts of the proppant material 112 to be blended withthe fracture fluid 134, using conventional sand logistics and on-padhandling equipment. Accordingly, the solid feed pump assembly 104 iscapable of operating continuously, in contrast to semi-batch operatingmodes of the state of the art lock hoppers.

Further embodiments of an apparatus for delivering a fluid using directinjection of a proppant at ambient pressure to a pressurized blender areillustrated in FIGS. 2-4. More particularly, illustrated are alternateembodiments of the solid feed pump assembly 104 as described in FIG. 1.Each of the embodiments of FIGS. 2-4 addresses the direct delivery of adry proppant material, such as proppant material 112 of FIG. 1, to apump assembly for pressurization and subsequent mixing with the fracturefluid 134 in a pressurized mixing apparatus 124. More particularly, eachof the embodiments of FIGS. 2-4 describes a pump assembly that may beutilized for the solid feed pump assembly 104, as described in FIG. 1.Accordingly, like numbers are used to identify like elements throughoutthe described embodiments and in an effort to provide a concisedescription of these embodiments, like features and elements previouslydescribed will not be further described.

Referring more specifically to FIG. 2, illustrated is an embodiment ofan apparatus for delivering a fluid mixture, generally referenced 200.The apparatus 200 includes a proppant storage vessel 102 configured tocontain therein a proppant material 112 and output a proppant outputflow 118 at ambient pressure. A solid feed pump assembly 104 is providedand coupled to the proppant storage vessel 102. The solid feed pumpassembly 104 includes a proppant inlet 106 in fluidic communication withthe proppant storage vessel proppant output flow 118. In this particularembodiment, the solid feed pump assembly 104 is a Posimetric® pumpassembly 202. The Posimetric® pump assembly 202 employspositive-displacement action to feed the proppant material 112 into thepressurized blender without the need for a pressurizing fluid. ThePosimetric® pump assembly 202 does not employ screws, augers, belts orvibratory trays to convey the proppant material 112, and in contrastemploys at least one vertical rotating spool 204 disposed within a pumpbody 208 to move the proppant material 112 therein. The proppant outputflow 118 is initially input at an input duct 206 that is coupled to thepump body 208. As the proppant output flow 118 enters and fills the pumpassembly 202, and more particularly the pump body 208, from above, thematerial locks itself firmly into the confines of the rotating spool 204contained therein, which carries it through an arc of approximately180°. More particularly, the proppant output flow 118 is rotated withinthe rotating spool 204, housed within the pump body 208, where itbecomes “locked up” or compacted so as to act as a solid mass, anddischarged via an output duct 210 at the outlet 120 as a proppant outputflow 122. While within the pump body 208, the proppant material 118 actsas a solid mass and a seal against the high pressure outlet. At the timeof discharge via the outlet 120, the proppant material output flow 122is output at an increased pressure, and more particularly at a fractureblending pressure that is higher than ambient pressure.

In a preferred embodiment, the Posimetric® pump assembly 202 includes aconsolidation section 212, a rotating section 214 and a dischargesection 216. During operation, the proppant material 112 enters the pumpassembly 202 and becomes consolidated as the individual proppantmaterial particles settle and come into contact with each other as wellas the sidewalls defining the pump body 208, the particles becomecompacted and act as a solid mass and form a seal against the highpressure outlet environment. As the proppant material 112 rotates in therotating spool 204 and pump body 208, the pressure of the proppantmaterial 112 is increased to the fracture blending pressure. Dischargeof the proppant material 112 at the increased fracture blending pressureoccurs upon rotating of the rotating spool 204 to the outlet 120.Exemplary pump assemblies are described in commonly assigned U.S. Pat.No. 8,006,827, D. Aldred et al., “Transporting Particulate Material”,issued Aug. 3, 2011, which is incorporated by reference herein in itsentirety.

The Posimetric® pump assembly 202 is configured to output the proppantoutput flow 122 at a fracture fluid blending pressure, wherein thefracture fluid blending pressure is greater than the ambient pressure.The apparatus 200 further includes a fracturing fluid storage vessel 128configured to contain therein a fracturing fluid 134 and output afracturing fluid output flow 136 at or above the fracture fluid blendingpressure. A pressurized blender, or mixing apparatus, 124 is coupled tothe Posimetric® pump assembly 202 to receive the discharged proppantoutput flow 122 therefrom and to the fracturing fluid storage vessel128. The mixing apparatus 124 is configured to mix the proppant outputflow 122 and the fracturing fluid output flow 136 therein and output afluid mixture 138 of proppant and fracturing fluid at the fracture fluidblending pressure. A fracturing fluid booster pump 141 and a highpressure pump assembly 142 are coupled to the mixing apparatus 124 andconfigured to deliver a high pressure fluid mixture 148 therein to adownstream component 146 at an injection pressure, wherein the injectionpressure is greater than the fracture fluid blending pressure.

Referring more specifically to FIG. 3, illustrated is another embodimentof an apparatus for delivering a fluid mixture, generally referenced300. The apparatus 300 includes a proppant storage vessel 102 configuredto contain therein a proppant material 112 and output a proppant outputflow 118 at ambient pressure. The apparatus 300 further includes afracturing fluid storage vessel 128 configured to contain therein afracturing fluid 134 and output a fracturing fluid output flow 136 at orabove a fracture fluid blending pressure, wherein the fracture fluidblending pressure is greater than the ambient pressure as previouslydescribed. A solid feed pump assembly 104 is provided and coupled to theproppant storage vessel 102 and the fracturing fluid storage vessel 128.The solid feed pump assembly 104 includes a proppant inlet 106 influidic communication with the proppant storage vessel proppant outputflow 118 and a fracture fluid inlet 324 in fluidic communication with atleast a portion of the fracturing fluid output flow 136. In thisparticular embodiment, the solid feed pump assembly 104 is an eductorpump assembly 302. During operation, the eductor pump assembly 302employs the Venturi effect of a converging-diverging nozzle to convertthe pressure energy of a motive fluid, and more particularly a portionof the fracturing fluid output flow 136, to velocity energy to feed theproppant material 112. Similar to the previously described Posimetric®pump assembly 202, the eductor pump assembly 302 does not employ screws,augers, belts or vibratory trays to convey the proppant material 112within the pump assembly toward the downstream components.

As illustrated in FIG. 3, the proppant output flow 118 is initiallyinput into the eductor pump assembly 302 via an input duct 306 that iscoupled to a pump body 308. The input of the proppant storage vesselproppant output flow 118 may be metered by a valve mechanism (not shown)disposed in the input duct 306. In an embodiment, the eductor pumpassembly 302 further includes a first converging nozzle 310, a secondconverging nozzle 312, a mixing chamber 314 and a diffuser, or expansionfeature, 316.

In an embodiment, the eductor pump assembly 302 includes the eductorbody 308, and more particularly a suction chamber 318 that is driven bythe motive fluid, and more particularly at least a portion of thefracturing fluid output flow 136 utilized as a motive flow. In anembodiment, at least a portion of the fracturing fluid output flow 136is input directly into the mixing apparatus 124. The fracturing fluidoutput flow 136 is accelerated through the first converging nozzle 310.As with traditional eductors, accelerating a higher pressure fluidthrough the first converging nozzle 310 drops the static pressure of amotive flow exiting through the first converging nozzle 310, whilesimultaneously decreasing the static pressure within the suction chamber318. The lower suction pressure in the suction chamber 318 draws in theproppant output flow 118, as a suction flow via the inlet port 106 ofthe eductor pump assembly 302. Subsequently, a fluid mixture 320,comprised of a combination of the proppant output flow 118 and thefracturing fluid output flow 136, is delivered to the second convergingnozzle 312 prior to reaching the mixing chamber 314. Within the mixingchamber 314 the fluid mixture 320, comprised of the proppant output flow118 and the fracturing fluid output flow 136, is further mixed as thestratifications between the two fluids is allowed to settle out and asthe turbulent fluid structure is reduced. The fluid mixture 320 exitingthe mixing chamber 314 is expanded in the expansion feature 316, priorto being delivered to the downstream components that may ultimately bein fluidic communication with a wellhead. The expansion feature 316provides an expansion of the fluid mixture 320 and provides a decreasein the velocity of the fluid mixture 320 and recovery of the pressure ofthe fluid mixture 320 allowing the fluid to be delivered to a mixingapparatus 124 at a fracture blending pressure.

During operation of the apparatus 300, including the eductor pumpassembly 302, the eductor pump assembly 302 is placed in operation bypressurizing the suction chamber 318. Subsequent to the appropriatepressure condition being reached, an optional valve mechanism or gate,322, disposed between the proppant storage vessel 102 and the inlet port106 may be opened to allow the proppant storage vessel 102 contents toenter the eductor pump assembly 302, and more particularly the suctionchamber 318. The suction chamber 318 draws in the proppant output flow118, including the proppant material 112, as the suction flow, andsubsequently mixes with the motive flow, and more particularly, at leasta portion of the fracturing fluid output flow 136. Operation of theapparatus may be continuous with continuous flow of the proppant outputflow 118 and the fracturing fluid output flow 136.

It should be noted that valve mechanism 322 is optional, being requiredin an application where the desire is to allow the eductor pump assembly302 to remain at full pressure. As valves in the direct path of theproppant output flow 118, and more particularly proppant material 112,it will be subject to a harsh abrasive environment, it is realized thatvalve mechanism 322 will be subject to higher wear rates. As such, anembodiment eliminating the valve mechanism 322 is anticipated.

The eductor pump assembly 302 is configured to output a proppant outputflow 122 at a fracture fluid blending pressure, wherein the fracturefluid blending pressure is greater than the ambient pressure. Theapparatus 300 further includes a pressurized blender, or mixingapparatus, 124 coupled to the eductor pump assembly 302 to receive thedischarged proppant output flow 122 therefrom and the fracturing fluidoutput flow 136. The mixing apparatus is configured to mix the proppantoutput flow 122 and the fracturing fluid output flow 136 therein andoutput a fluid mixture output flow 138 of proppant and fracturing fluidat the fracture fluid blending pressure. A fracturing fluid booster pump141 and a high pressure pump assembly 142 are coupled to the mixingapparatus 124 and configured to deliver the fluid mixture 138 therein toa downstream component 146 as a high pressure fluid mixture output flow148 at an injection pressure, wherein the injection pressure is greaterthan the fracture fluid blending pressure.

Accordingly, the inclusion of the eductor pump assembly 302, asdescribed in apparatus 300, provides for the pressurizing of thefracturing fluid 134 in a conventional high pressure fluid pump and thenuse that at least a portion of the flow of high-pressure fracturingfluid 136 as the motive fluid flow through the eductor pump assembly 302to convey the proppant 112 and more particularly the proppant outputflow 118 into the flowing motive fluid.

Referring more specifically to FIG. 4, illustrated is another embodimentof an apparatus for delivering a fluid mixture, generally referenced400. The apparatus 400 includes a proppant storage vessel 102 configuredto contain therein a proppant material 112 and output a proppant outputflow 118 at ambient pressure. The apparatus 400 further includes afracturing fluid storage vessel 128 configured to contain therein afracturing fluid 134 and output a fracturing fluid output flow 136 at orabove a fracture fluid blending pressure, wherein the fracture fluidblending pressure is greater than the ambient pressure as previouslydescribed. A solid feed pump assembly 104 is provided and coupled to theproppant storage vessel 102 and the fracturing fluid storage vessel 128.The solid feed pump assembly 104 includes a proppant inlet 106 influidic communication with the proppant storage vessel proppant outputflow 118. In this particular embodiment, the solid feed pump assembly104 is positive displacement pump, and more particularly a rotary-typepositive displacement pump, such as an internal gear, screw or augertype pump assembly, referenced 402. The unique design of the positive,displacement pump 402, ensures that the proppant material 112 isconstantly present at a feed inlet 404, while the controlled rotation ofa feed mechanism 406 moves the proppant material 112, and moreparticularly the proppant output flow 118, from the feed inlet 404 to adischarge point 408. In the illustrated embodiment, the feed mechanism406 comprises a screw mechanism 410 (a helical surface surrounding acentral cylindrical shaft) disposed inside a hollow body 412.

As illustrated in FIG. 4, the proppant output flow 118 is initiallyinput into the rotary-type positive displacement pump 402 via the feedinlet 404. Similar to the previous embodiment, the input of the proppantstorage vessel proppant output flow 118 may be metered by an optionalvalve mechanism (not shown). Similar to the Posimetric® pump assembly202 of FIG. 1, the positive displacement pump assembly 402 employspositive-displacement action to feed the proppant material 112 as afree-flowing material with a uniform discharge in a linear volumetricfashion. In contrast to the Posimetric® pump assembly 202, the positivedisplacement pump assembly 402 employs screws, augers, belts orvibratory trays to convey the proppant material 112 therein. Theproppant output flow 118 is initially input at the feed inlet 404 thatis coupled to the pump body 412. As the proppant output flow 118 entersand fills the pump assembly 402, and more particularly the pump body412, the material is carried by the feed mechanism 406 containedtherein, toward the discharge point 408. The proppant output flow 118 isrotated within the feed mechanism 406, housed within the pump body 412and discharged via an output duct 414 at the discharge point 408 as aproppant output flow 122. At the time of discharge via an outlet 120,the proppant material output flow 122 is output at an increasedpressure, and more particularly at a fracture blending pressure that ishigher than ambient pressure.

In a preferred embodiment, during operation, the proppant material 112enters the rotary-type positive displacement pump 402 at the feed inlet404. As the proppant material 112 rotates in the feed mechanism 410 andpump body 412, the pressure of the proppant material 112 is increased tothe fracture blending pressure. Discharge of the proppant material 112at the increased fracture blending pressure occurs upon rotation of thefeed mechanism 406 to the outlet 120.

The rotary-type positive displacement pump 402 is configured to outputthe proppant output flow 122 at a fracture fluid blending pressure,wherein the fracture fluid blending pressure is greater than the ambientpressure. The apparatus 400 further includes a pressurized blender, ormixing apparatus, 124 coupled to the rotary-type positive displacementpump 402 to receive the discharged proppant output flow 122 therefromand the fracturing fluid output flow 136. The mixing apparatus 124 isconfigured to mix the proppant output flow 122 and the fracturing fluidoutput flow 134 therein and output a fluid mixture 138 of proppantmaterial 112 and fracturing fluid 134 at the fracture fluid blendingpressure. A high pressure pump assembly 142 coupled to the mixingchamber 124 is configured to deliver a high pressure fluid mixture 148to a downstream component 146 at an injection pressure, wherein theinjection pressure is greater than the fracture fluid blending pressure.In this particular embodiment, a separate booster pump is not provided,and in in lieu of boosting of the fracturing fluid pressure is providedas part of the functionality of the high pressure pump assembly 142.

Accordingly, the inclusion of the rotary-type positive displacement pump402, as described in apparatus 400, provides for the pressurizing of thefracturing fluid 134 in a conventional high pressure fluid pump. Theproppant 112 does not flow through a conventional high pressure fluidpump, or pumps, thereby minimizing degradation to these pumps thatpumping the proppant 112 through them would cause.

FIG. 5 is a schematic block diagram of a method 500 of delivering afluid mixture using direct proppant injection to a pressurized blenderusing a solid feed pump assembly in an apparatus 100, 200, 300 accordingto an embodiment disclosed herein. Generally, the method involvesproviding an input of a proppant material 112 to a proppant storagevessel 102, and providing an input of a fracture fluid 134 to a fracturefluid storage vessel 128, at a step 502. Next in step 504, a proppantoutput flow 118 at ambient pressure from the proppant storage vessel 102is input into a solid feed pump assembly 104. As previously described,the solid feed pump assembly 104 may be configured as a positivedisplacement pump assembly, and more particularly a Posimetric® pumpassembly 202 (as best illustrated in FIG. 2) or a rotary-type positivedisplacement pump 402 (as best illustrated in FIG. 4) or as an eductorpump assembly 304 (as best illustrated in FIG. 3). Next in step 506, theproppant output flow 118 and a fracturing fluid output flow 136 areinput to a mixing apparatus 124. In an embodiment, the fracturing fluidoutput flow 136 is input to the mixing apparatus 124 via an eductor pumpassembly. The mixing apparatus 124 is configured to mix the proppantoutput flow 118 and the fracturing fluid output flow 136 therein andoutput a fluid mixture output flow 138 of the proppant and fracturingfluid at the fracture fluid blending pressure, at step 508. The pressureof the fluid mixture output flow 138 is next increased in a highpressure pump 142, at step 510. Subsequently the high pressure fluidmixture 148 is delivered to one or more downstream components 146, at astep 512, and ultimately may include delivery to a well head.

Additional commercial advantages of the disclosed apparatus are relatedto the current problem faced in unconventional gas development and therequirement to mix/blend chemicals and a proppant, namely sand withfracturing fluids (e.g., liquid CO₂, liquid propane gas) that requirethey always be contained at a suitable fracture fluid blending pressureto avoid vaporization of these fracturing fluids. Accordingly, disclosedis apparatus and method of delivering a fluid mixture using a solid feedpump assembly and direct proppant injection into a pressurized mixingapparatus in such a way that a continuous flow of proppant can beprovided without being constrained by the total volume limits of theknown lock hopper based approaches.

The foregoing has described an apparatus and method of delivering afluid mixture using direct injection of a proppant into a pressurizedmixing apparatus. While the present disclosure has been described withrespect to a limited number of embodiments, those skilled in the art,having benefit of this disclosure, will appreciate that otherembodiments may be devised which do not depart from the scope of thedisclosure as described herein. While the present disclosure has beendescribed with reference to exemplary embodiments, it will be understoodby those skilled in the art that various changes may be made andequivalents may be substituted for elements thereof without departingfrom the scope of the disclosure. In addition, many modifications may bemade to adapt a particular situation or material to the teachings of thepresent disclosure without departing from the essential scope thereof.Therefore, it is intended that the present disclosure not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out the disclosure. It is, therefore, to be understood that theappended claims are intended to cover all such modifications and changesas fall within the true spirit of the disclosure.

1. An apparatus for delivering a fluid mixture comprising: a proppantstorage vessel configured to contain therein a proppant material andoutput a proppant output flow at ambient pressure; a solid feed pumpassembly coupled to the proppant storage vessel, the solid feed pumpassembly including a proppant inlet in fluidic communication with theproppant storage vessel proppant output flow, the solid feed pumpassembly configured to output a proppant output flow at a dischargepressure, wherein the discharge pressure is greater than the ambientpressure; a fracturing fluid storage vessel configured to containtherein a fracturing fluid and output a fracturing fluid output flow ata fracture fluid blending pressure, wherein the fracture fluid blendingpressure is greater than the ambient pressure; a pressurized mixingapparatus coupled to the solid feed pump assembly, the pressurizedmixing apparatus including a proppant inlet in fluidic communicationwith the solid feed pump assembly proppant output flow and a fracturingfluid inlet in fluidic communication with the fracturing fluid outputflow, the pressurized mixing apparatus configured to mix the proppantoutput flow and the fracturing fluid output flow therein and output afluid mixture of proppant and fracturing fluid, wherein the fracturingfluid of the fluid mixture of proppant and fracturing fluid is at thefracture fluid blending pressure; and a pump assembly coupled to thepressurized mixing chamber and configured to deliver the fluid mixtureof proppant and fracturing fluid therein to a downstream component at aninjection pressure, wherein the injection pressure is greater than thefracture fluid blending pressure.
 2. The apparatus of claim 1, whereinthe solid feed pump assembly is a solid feed pump assembly set forth bythe Posimetric® standard.
 3. The apparatus of claim 1, wherein the solidfeed pump assembly is an eductor pump assembly.
 4. The apparatus ofclaim 1, wherein the solid feed pump assembly is a rotary positivedisplacement pump assembly.
 5. The apparatus of claim 1, wherein thefracture fluid blending pressure is in a range of 200-400 psi.
 6. Theapparatus of claim 5, wherein the fracture fluid blending pressure isapproximately 300 psi.
 7. The apparatus of claim 1, wherein theinjection pressure is in a range of 5000-12,000 psi or higher.
 8. Theapparatus of claim 1, wherein the injection pressure is approximately10,000 psi.
 9. The apparatus of claim 1, wherein the proppant materialis sand.
 10. The apparatus of claim 1, wherein the fracturing fluid isat least one of liquid CO₂ or liquid propane.
 11. The apparatus of claim1, wherein the solid feed pump assembly is configured to receive acontinual supply of proppant material and output a continuous proppantoutput flow.
 12. An apparatus for delivering a fluid mixture comprising:a proppant storage vessel configured to contain therein a proppantmaterial and output a proppant output flow at ambient pressure; a solidfeed pump assembly coupled to the proppant storage vessel, the solidfeed pump assembly including a proppant inlet in fluidic communicationwith the proppant storage vessel proppant output flow, the solid feedpump assembly configured to output a proppant output flow at a dischargepressure, wherein the discharge pressure is greater than the ambientpressure, wherein the solid feed pump assembly is one of a solid feedpump assembly set forth by the Posimetric® standard, an eductor pumpassembly or a rotary positive displacement pump assembly; a fracturingfluid storage vessel configured to contain therein a fracturing fluidand output a fracturing fluid output flow at a fracture fluid blendingpressure, wherein the fracture fluid blending pressure is greater thanthe ambient pressure; a mixing apparatus coupled to the solid feed pumpassembly, the mixing apparatus including a proppant inlet in fluidiccommunication with the solid feed pump assembly proppant output flow anda fracturing fluid inlet in fluidic communication with the fracturingfluid output flow, the mixing apparatus configured to mix the proppantoutput flow and the fracturing fluid output flow therein and output afluid mixture of proppant and fracturing fluid, wherein the fracturingfluid is at the fracture fluid blending pressure; and a pump assemblycoupled to the mixing chamber and configured to deliver the fluidmixture therein to a downstream component at an injection pressure,wherein the injection pressure is greater than the fracture fluidblending pressure.
 13. The apparatus of claim 12, wherein the fracturefluid blending pressure is in a range of 200-400 psi.
 14. The apparatusof claim 13, wherein the fracture fluid blending pressure isapproximately 300 psi.
 15. The apparatus of claim 12, wherein theinjection pressure is in a range of 5000-12,000 psi.
 16. The apparatusof claim 12, wherein the proppant material is sand and the fracturingfluid is at least one of liquid CO₂ or liquid propane.
 17. The apparatusof claim 12, wherein the solid feed pump assembly is a solid feed pumpassembly set forth by the Posimetric® standard coupled to the proppantstorage vessel, the solid feed pump assembly comprising: a consolidationsection configured to cause the proppant material to compact and act asa solid mass; a rotating section configured to increase the pressure ofthe proppant material therein; and a discharge section configured todischarge the proppant material at the increased discharge pressure. 18.The apparatus of claim 12, wherein the solid feed pump assembly is aneductor pump assembly coupled to the proppant storage vessel and thefracturing fluid storage vessel, the eductor pump assembly comprising: asuction chamber in fluidic communication with the proppant output flow,the fracture fluid output flow and a motive fluid flow, the suctionchamber configured to output a fluid mixture to a mixing chamber; and anexpansion feature coupled to the mixing chamber and configured to expandthe fluid mixture therein for delivery to a downstream component. 19.The apparatus of claim 12, wherein the solid feed pump assembly isrotary positive displacement pump assembly coupled to the proppantstorage vessel, the rotary positive displacement pump assemblycomprising: a pump body, including a feed inlet at a first end and adischarge point at a second end; a feed mechanism disposed within thepump body and configured to move the proppant material from the feedinlet to the discharge point while increasing a pressure of the proppantmaterial from an ambient pressure to the discharge pressure.
 20. Anapparatus for delivering a fluid mixture comprising: a proppant storagevessel configured to output a proppant output flow at ambient pressure;a solid feed pump in fluidic communication with the proppant storagevessel, the solid feed pump assembly configured to output a proppantoutput flow at a discharge pressure, wherein the discharge pressure isgreater than the ambient pressure; a fracturing fluid storage vesselconfigured to contain therein a fracturing fluid at a fracture fluidblending pressure, wherein the fracture fluid blending pressure isgreater than the ambient pressure; a mixing apparatus coupled to thesolid feed pump assembly and the fracturing fluid storage vessel, themixing apparatus configured to output a fluid mixture of proppant andfracturing fluid, wherein the fracturing fluid is at the fracture fluidblending pressure; and a pump assembly coupled to the mixing chamber andconfigured to output a fluid mixture to a downstream component at aninjection pressure, wherein the injection pressure is greater than thefracture fluid blending pressure.
 21. A method of delivering a fluidmixture, comprising: providing an input of a proppant material atambient pressure to a proppant storage vessel, the proppant storagevessel configured to output a proppant output flow at ambient pressure;providing an input of a fracture fluid at a fracture fluid blendingpressure to a fracture fluid storage vessel, the fracture fluid storagevessel configured to output a fracture fluid output flow at the afracture fluid blending pressure; inputting the proppant output flow atambient pressure from the proppant storage vessel into a solid feed pumpassembly wherein the pressure of the proppant output flow is increasedto a discharge pressure; inputting the proppant output flow at thedischarge pressure and a fracture fluid output flow at the fracturefluid blending pressure into a mixing apparatus; mixing the proppantoutput flow and the fracturing fluid output flow therein the mixingapparatus and outputting a fluid mixture of proppant and fracturingfluid, wherein the fracturing fluid is at the fracture fluid blendingpressure; increasing the pressure of the output fluid mixture in a pumpto output an increased pressure fluid mixture; and delivering theincreased pressure fluid mixture to one or more downstream components.